If you're looking for an inexpensive extra hammock, Overstock.com has this "Ultralight Travel Hammock" for $23:
http://www.overstock.com/Sports-Toys...8/product.html

Description:
Travel hammock is perfect to take on camping trips and other excursions.
Outdoor gear packs down to a mere 12 ounces and offers a comfortable, portable sleeping solution.
Hammock comes with everything you need and sets up in less than a minute.

This sounds a lot like that Parrot Bay cheapy that launched a big thread a couple months ago. I don't plan on buying one, but thought y'all might want to take a peek.